1. Field of the Invention
The present general inventive concept relates to an ion print head and an image forming apparatus using the same, and more particularly, to an ion print head in which a discharge cell array structure having microelectrodes is employed, and a image forming apparatus using the same.
2. Description of the Related Art
In a conventional image forming apparatus, a charged photoconductor is exposed to a laser beam, thereby forming a latent image on an image forming part. A toner is supplied between the photoconductor and a development roller to selectively adhere the toner on the image forming part according to an electrostatic property thereof. Herein, the development roller engages the photoconductor but has a different electrostatic potential than the photoconductor. Since the conventional image forming apparatus uses laser beams, a laser scanning unit is required to expose the photoconductor. However, the laser scanning unit requires a precise optical arrangement. Additionally, the laser scanning unit is expensive.
In an attempt to avoid these disadvantages associated with the conventional image forming apparatus that used the laser scanning unit, a printer with a conventional ion print head is disclosed in U.S. Pat. No. 5,406,314. The printer with the conventional ion print head of U.S. Pat. No. 5,406,314 is illustrated in FIGS. 1 and 2.
FIG. 1 is a schematic sectional view illustrating a printer that uses a conventional ion print head. Referring to FIG. 1, the printer includes an image cylinder 15 having a conductive layer 17 and a dielectric layer 16, and erase lamp 14, an electronic writing head 30 for charging the image cylinder 15 to have a predetermined pattern that corresponds to a latent image according to control exerted by a controller, an ink-supply roller 12 in contact with the image cylinder 15 for supplying ink while rotating, a transfer roller 18 for transferring the latent image formed on the image cylinder 15 to a printing medium 10, and a heating element 21 and a hot roller 23 for fusing the transferred image on the printing medium 10. A printing operation performed by the printer is as follows: the electronic writing head 30 forms the latent image having the predetermined pattern on the image cylinder 15, the ink-supply roller 12 supplies ink to the image cylinder 15, the supplied ink adheres on a latent image area of an outer surface of the image cylinder 15 to form an ink image thereon. The transfer roller 18 then transfers the ink image of the image cylinder 15 to the printing medium 10, which passes between the image cylinder 15 and the transfer roller 18. The heating element 21 and the hot roller 23 then fuse the transferred image on the printing medium 10.
FIG. 2 is a schematic sectional view illustrating the electronic writing head 30 of the conventional ion print head of FIG. 1.
Referring to FIG. 2, the electronic writing head 30 includes an insulating body 31, a needle electrode 35, a wraparound electrode 37, and a power supply 39 for supplying voltage pulses to the needle electrode 35. The insulating body 31 is spaced apart from the dielectric layer 16 in a perpendicular direction and has a tunnel 31a disposed therein. The needle electrode 35 is formed on an inside wall of the tunnel 31a and has a leading end pointing toward an opposite inner wall of the tunnel 31a. The wraparound electrode 37 is formed at a portion of the tunnel 31a that is adjacent to the dielectric layer 16.
Accordingly, when a voltage pulse is applied to the needle electrode 35, gas molecules in the proximity of the needle electrode 35 lose at least one electron under the influence of a strong electrostatic field created by the needle electrode 35. The electrons are then absorbed by the needle electrode 35. Positive ions from the gas molecules that lose at least one electron tend to migrate away from the needle electrode 35 to a lower electrical potential at a bottom portion of the tunnel 31a where the positive ions encounter and are neutralized by the wraparound electrode 37. The positive ions are more strongly attracted to the conductive layer 17 than by the wraparound electrode 37 because an electric potential of the conductive layer 17 is more negative than is an electric potential of the wraparound electrode 37. Thus, the positive ions can be accumulated on the dielectric layer 16 to form the latent image thereon.
The disadvantage of the conventional ion print head of the printer is that the needle electrode 35 in the insulating body 31 is arranged in a radial direction of the image cylinder 15 and the wraparound electrode 37 is additionally provided at the bottom of the tunnel 31a, thereby increasing complexity of the electronic writing head 30. Additionally, the process of accumulating the positive ions on the dielectric layer 16 of the image cylinder 15 is complicated.